Bearing assemblies, and related methods

ABSTRACT

Bearing components, bearing assemblies and related methods are provided. In one embodiment, a bearing element includes a base layer and a polycrystalline diamond (PCD) layer comprising a plurality of PCD elements coupled with the base layer wherein each PCD element comprising a substrate and a diamond table. The plurality of PCD elements may be fit together to form a substantially continuous bearing surface. For example, the diamond tables may exhibit substantially square or rectangular geometries that are fit together to define the bearing surface. In other embodiments, the bearing elements may be spaced apart from one another. In other embodiments, the bearing element may include a single PCD element formed from a prefabricated PCD compact or cutting tool blank. Various bearing assemblies may incorporate such a bearing element including, for example, thrust bearings, journal bearings, and tilting pad bearing assemblies.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.14/135,064 filed on 19 Dec. 2013, which is a continuation of U.S.application Ser. No. 13/550,825 filed on 17 Jul. 2012 (now U.S. Pat. No.8,646,981 issued on 11 Feb. 2014), which is a continuation-in-part ofU.S. application Ser. No. 13/089,725 filed on 19 Apr. 2011 (now U.S.Pat. No. 8,545,103 issued on 1 Oct. 2013), the disclosure of each of theforegoing applications is incorporated herein, in its entirety, by thisreference.

TECHNICAL FIELD

Embodiments of the present invention relate generally to bearingelements and bearing assemblies and, more particularly, to compositions,configurations, geometries and methods of manufacturing bearingcomponents and bearing assemblies.

BACKGROUND

Bearings are well known devices that enable relative movement two ormore components. A variety of different bearing types are known andutilized on a regular basis. So-called “thrust bearings” and someembodiments of radial bearings conventionally include bearing surfacesthat at least partially contact and move or slide relative to oneanother. Such bearing surfaces are conventionally prone to wear due totheir interaction with one another and, as such, are formed fromappropriate wear resistant materials. For example, such bearing surfacesmay include a superhard material for resisting wear during use of thebearing. In one particular example, at least one or both of the bearingsurfaces may be formed of a material comprising diamond (e.g.,polycrystalline diamond).

As noted above, bearings may be used in numerous applications. In oneexample, bearings may be used subterranean drilling equipment. Suchequipment may include drilling motors and drill bits having multiplecomponents that move relative to one another, such as roller cones, andmay be utilized for drilling boreholes into a subterranean formation,such as for oil or gas exploration. In a conventional downhole drillingmotor, the motor is suspended at the lower end of a string of drill pipecomprising a series of pipe sections connected together at joints andsupported from the surface. A rotary drill bit (e.g., a fixed cutterdrill bit, roller cone drill bit, a reamer, etc.) may be supported belowthe drilling motor (via pipe sections, drill collars, or otherstructural members as known in the art) or may be directly connected tothe downhole motor, if desired. Drilling fluid, which is commonly knownas drilling mud, is circulated through the pipe string and the motor togenerate torque within the motor to cause the rotary drill bit torotate. Bearings are conventionally used to enable efficient relativerotation of the rotary bit and other components of the drill string.

Many types of bearings may be used in such a drill string assembly,including the bearings that may be employed by a rotary drill bit. Oneparticular example includes radial bearings. In one embodiment, an innerand outer race are each provided with a plurality of superhard bearingelements (e.g., polycrystalline diamond elements). The races arepositioned adjacent one another so that the bearing surfaces of thebearing elements contact one another during starting and stopping oroverload conditions. In fluid bearings, the surfaces of the races do notcontact during normal operation but, instead, are separated by a fluidfilm. As may be appreciated, geometry and configuration of the bearingelements of the races may be an important factor influencing theperformance and life of such a bearing structure. Examples of someconventional radial bearing apparatuses are disclosed by U.S. Pat. Nos.4,662,348, 4,729,440, 4,738,322, 4,756,631, and 4,764,036, thedisclosures of each of which are incorporated, in their entireties, bythis reference. Another example of a bearing used in drill stringassembly includes a thrust bearing. A thrust bearing enables rotationbetween two adjacent components while also supporting a high level ofaxial thrust. Some examples of a thrust bearing assemblies are set forthin U.S. Pat. Nos. 7,552,782 and 7,870,913, the disclosures of each ofwhich are incorporated, in their entireties, by this reference.

It is a continued desire within the industry to provide improved bearingelements and apparatuses including such elements.

SUMMARY

Embodiments of the present invention are directed to various bearingelements, bearing assemblies and related methods. In accordance with oneembodiment of the invention, a bearing assembly is provided. The bearingassembly includes a first tilting pad bearing assembly comprising a bodyand plurality of tilting pad bearings. Each tilting pad bearing includesa polycrystalline diamond (PCD) layer attached to a base layer. Theplurality of tilting pad bearings being circumferentially spaced aboutthe body defining a first collective bearing surface. The bearingassembly also includes a runner bearing comprising a PCD layer having aplurality of PCD elements coupled to a base layer defining a secondcollective bearing surface. The first tilting pad bearing assembly andthe runner bearing are positioned and configured to move relative toeach other with the first collective bearing surface being in contactwith the second collective bearing surface.

In one embodiment, each of the plurality PCD elements of the runnerbearing is contiguous with an adjacent one of the plurality of PCDelements to define a substantially continuous surface. The PCD elementsof the runner bearing may exhibit an annular sector geometry in oneembodiment. In another embodiment, at least some of the plurality of PCDelements may include a surface exhibiting a substantially squaregeometry.

In another embodiment, the plurality of PCD elements of the runnerbearing are spaced apart from one another such that there is a gapbetween adjacent PCD elements. One or more of the PCD elements of therunner bearing may exhibit a substantially cylindrical geometry.

Additionally, in one embodiment, the PCD layer of at least one tiltingpad bearing includes a plurality of PCD elements. In such an embodiment,each of the plurality PCD elements of the tilting pad bearing may bepositioned to be contiguous or in direct contact with one or moreadjacent PCD elements of the tilting pad bearing to define asubstantially continuous surface. In another embodiment, the PCDelements may be spaced apart from one another such that there is a gapbetween adjacent PCD elements. The PCD elements may exhibit a variety ofgeometries.

In one embodiment, the runner bearing further comprises a second PCDlayer comprising another plurality of PCD elements coupled to the baselayer defining a third collective bearing surface. Additionally, thebearing assembly may include a second tilting pad bearing assemblyhaving a body and plurality of tilting pad bearings, each tilting padbearing of the second assembly comprising a polycrystalline diamond(PCD) layer attached to a base layer, the plurality of tilting padbearings of the second assembly being circumferentially spaced about thebody of the second assembly and defining a fourth collective bearingsurface. The second tilting pad bearing assembly and the runner bearingmay be positioned and configured to move relative to each other with thethird collective bearing surface being in contact with the fourthcollective bearing surface.

In accordance with another embodiment of the present invention, abearing element is provided. The bearing element includes a base layerand a polycrystalline diamond (PCD) layer. The PCD layer includes aplurality of PCD elements coupled with the base layer with each PCDelement comprising a substrate and a diamond table.

In one particular embodiment, each of the plurality PCD elements iscontiguous with an adjacent one of the plurality of PCD elements todefine a substantially continuous surface. The substantially continuoussurface may exhibit various geometries. For example, in one embodimentthe substantially continuous surface is shaped as an annular sector. Inanother embodiment the substantially continuous surface exhibits asubstantially circular geometry.

In another embodiment, the plurality of PCD elements are spaced apartfrom one another such that there is a gap between adjacent PCD elements.

The PCD elements may also exhibit various geometries. Such geometriesmay include providing a diamond table surface that is substantiallysquare, rectangular circular or other geometries.

In one embodiment, the base layer of the bearing element may comprisetungsten carbide. In such an embodiment, the substrate may likewisecomprise tungsten carbide. In another embodiment, the base layer maycomprise steel.

In one embodiment, the bearing element may be formed as a tilting padbearing element. In such a case, a projection may be formed on the baselayer to enable the bearing element to rock relative to other componentswithin a bearing assembly. In another embodiment, when formed as atilting pad bearing, the base layer may be formed to exhibit an arcuatesurface.

In accordance with another embodiment to the present invention, a methodis provided for manufacturing a bearing element. The method includesforming at least one polycrystalline diamond compact (PDC) having adiamond table and a substrate under high-pressure, high-temperatureconditions. The at least one PDC is attached to a base layer. In oneembodiment, forming at least one PDC includes forming a plurality ofPDCs and attaching them to the base layer. The method may furtherinclude arranging the plurality of PDCs to form a substantiallycontinuous bearing surface. In another embodiment, the method mayinclude spacing the plurality of PDCs from each other such that a gapexists between adjacent PDCs.

Attaching the PDC(s) to the base layer may include a brazing process inone embodiment. In another embodiment, attaching the PDC(s) to the baselayer may include an e-beam welding process. In yet another embodiment,attaching the PDC(s) to the base layer may include clamping the PDC(s)using one or more clamps or other fastening mechanisms.

Other features, aspects and embodiments are set forth herein as willbecome apparent upon review of the detailed description. It is notedthat features of one described embodiment herein may be combined withfeatures of other described embodiments without limitation.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The foregoing and other advantages of embodiments of the invention willbecome apparent upon reading the following detailed description and uponreference to the drawings in which:

FIG. 1A shows a perspective view of an embodiment of a bearing assemblyaccording to the present invention;

FIG. 1B shows an exploded view of the assembly shown in FIG. 1A;

FIG. 1C shows a partial cross-sectional view of the assembly shown inFIG. 1A;

FIG. 2A shows a top view and FIGS. 2B and 2C show respective side viewsof embodiments of bearing elements that may be used in a bearingassembly such as shown in FIGS. 1A-1C;

FIG. 3A shows a top view and FIGS. 3B and 3C show respective side viewsof further embodiments of bearing elements that may be used in a bearingassembly such as shown in FIGS. 1A-1C;

FIG. 4 shows a side view of certain components of the bearing assemblyshown in FIGS. 1A-1C;

FIGS. 5A and 5B show perspective views of different embodiments ofbearing elements that may be used in various bearing assemblies of thepresent invention;

FIGS. 6A and 6B show perspective views of different embodiments ofanother bearing component of the bearing assembly shown in FIGS. 1A-1C;

FIGS. 7A and 7B show a perspective views of bearing components accordingto other embodiments;

FIGS. 8A and 8B show respective top and cross-sectional views of abearing component according to another embodiment;

FIG. 8C is an enlarged, cross-sectional view a PCD component;

FIG. 9A shows a top view and FIGS. 9B-9D show respective cross-sectionalviews of a bearing component according to a further embodiment

FIGS. 10A and 10B show respective top views of various embodiments ofbearing elements;

FIG. 11 shows a top view of a component of a bearing assembly;

FIG. 12 shows a top view of a component of a bearing assembly;

FIGS. 13A-13E show respective side views of various embodiments ofbearing elements;

FIGS. 14A and 14B show side views of additional embodiments of bearingelements;

FIG. 15A shows a top view of a bearing element component;

FIG. 15B shows a cross-sectional view of the bearing element componentof FIG. 15A;

FIG. 15C shows a partial cross-sectional view of the bearing elementcomponent of FIGS. 15A and 15B assembled with a backing member;

FIGS. 16A-16D show a top and various cross-sectional views,respectively, of bearing components;

FIG. 17 shows a perspective view of a bearing assembly;

FIG. 18A shows a perspective view of various components of the bearingassembly shown in FIG. 10;

FIG. 18B shows an exploded view of the components shown in FIG. 18A;

FIG. 18C shows a partial side view of the components shown in FIGS. 18Aand 11B;

FIGS. 19A and 19B show end and perspective views, respectively, of abearing element;

FIG. 20 shows a plan view of a fabrication component used in formingbearing elements that may be used in the bearing assemblies of thepresent invention;

FIGS. 21A and 21B show perspective and partial cross-sectional views,respectively, of a component of a bearing assembly;

FIGS. 22A and 22B show end and perspective views, respectively, of abearing element;

FIGS. 23A and 23B show front and cross-sectional views, respectively, ofa component of a bearing assembly;

FIGS. 24A and 24B show front and cross-sectional views, respectively, ofa component of a bearing assembly;

FIGS. 25A and 25B show front and cross-sectional views, respectively, ofa component of a bearing assembly;

FIG. 26 is a perspective view of a bearing component for a bearingassembly;

FIG. 27 is a perspective view of a bearing component for a bearingassembly;

FIG. 28 shows a side view of a component of a bearing assembly; and

FIG. 29 is a partial cross-sectional view of a pump incorporatingvarious bearing assemblies.

DETAILED DESCRIPTION

Embodiments of the present invention relates generally to bearingelements and apparatuses that may include bearing surfaces comprisingsuperhard materials. “Superhard,” as used herein, refers to any materialhaving a hardness that is at least equal to or exceeds a hardness oftungsten carbide (e.g., without limitation, polycrystalline diamond,boron nitride, silicon carbide, silicon nitride, aluminum nitride,aluminum oxide, titanium diboride, yttrium oxide, boron carbide andmixtures of the foregoing). For example, in one embodiment, apolycrystalline diamond compact (PDC), or multiple PDCs, may be used toform a bearing surface in the bearing elements and apparatuses of thepresently disclosed invention. In another embodiment, polycrystallinediamond may include nanodiamond (i.e., ultra-dispersed diamond), ifdesired. In yet another example, the bearing surface may include asilicon carbide and diamond composite material such as is disclosed inU.S. Pat. No. 7,060,641, the disclosure of which is incorporated herein,in its entirety, by this reference. A variety of other superhardmaterials may be utilized in forming a superhard bearing in accordancewith the presently disclosed invention as will be appreciated by thoseof ordinary skill in the art.

Considering the example of a PDC, a PDC is conventionally fabricated byplacing a cemented carbide substrate into a container or cartridge witha layer of diamond crystals or grains positioned adjacent one surface ofa substrate. A number of such cartridges may be typically loaded into anultra-high pressure press. The substrates and adjacent diamond crystallayers are then sintered under ultra-high temperature and ultra-highpressure (“HPHT”) conditions. The ultra-high pressure and ultra-hightemperature conditions cause the diamond crystals or grains to bond toone another to form polycrystalline diamond with diamond-to-diamondbonds. Additionally, as known in the art, a catalyst may be employed forfacilitating formation of polycrystalline diamond. In one example, aso-called “solvent catalyst” may be employed for facilitating theformation of polycrystalline diamond. For example, cobalt, nickel, andiron are some non-limiting examples of solvent catalysts that may beused in forming polycrystalline diamond.

In one configuration, during sintering, the solvent catalyst may includethe substrate body (e.g., cobalt from a cobalt-cemented tungsten carbidesubstrate). In such a case, the solvent catalyst from the substratebecomes liquid and sweeps from the region adjacent to the diamond powderand into the diamond grains. In another embodiment, a solvent catalystmay be mixed with the diamond powder prior to sintering, either in lieuof, or in addition to, the existence of a solvent catalyst in thesubstrate. Thus, diamond grains become mutually bonded to form apolycrystalline diamond table upon the substrate. A conventional processfor forming polycrystalline diamond structures is disclosed in U.S. Pat.No. 3,745,623 to Wentorf, Jr. et al., the disclosure of which isincorporated, in its entirety, by this reference.

The solvent catalyst may remain in the polycrystalline diamond layerwithin the interstitial pores between the diamond grains or may be atleast partially removed to a desired depth, such as by leaching (e.g.,exposing at least a portion of the diamond table to an acid) or by anyother suitable method. Removal of the catalyst may enhance the thermalstability of the PDC material. Optionally, another material may replacethe solvent catalyst that has been at least partially removed from thepolycrystalline diamond.

In one embodiment, a bearing apparatus may include polycrystallinediamond (or other superhard) inserts or compacts that define a pluralityof bearing surfaces that move relative to one another. Such bearingapparatuses may encompass so-called thrust bearings, radial bearings, orother bearing apparatuses having bearing surfaces that move in relationto one another. Bearing apparatuses described herein may include tiltingpad bearings. Tilting pad bearings are generally used in high speedmachinery operating under medium to high loads (e.g., turbines, pumps,turbocompressors and high speed gearboxes). They offer the optimumsolution to any particular requirement because of their utility toautomatically adjust to varying conditions. Various bearing elementconstructions, bearing assemblies and related methods of manufacturingand operating such components are described herein.

Various systems and assemblies using the described bearing apparatusesare contemplated, including, for example, various components associatedwith drilling strings and down hole drilling tools. For example, aradial bearing according to the present invention may be included withina motor or turbine. Generally, such a downhole drilling motor assemblymay be located at the end of a series of pipe sections comprising adrill string. The housing of downhole drilling motor assembly may remainstationary as a rotary drill bit coupled thereto rotates. Thus, anoutput shaft of a downhole drilling motor assembly may be coupled to arotary drill bit and drilling fluid (i.e., drilling mud) may causetorque to be applied to the output shaft to cause a rotary drill bit torotate. Thus, such a downhole drilling motor or turbine assembly mayinclude one or more radial bearing apparatuses. Of course, the bearingcomponents and assemblies described herein are not limited to use insubterranean drilling equipment and applications. Rather, the describedcomponents and assemblies may be used in various mechanical systems andapplications.

The use of polycrystalline diamond (PCD) in assemblies that include, forexample, tilting pad bearings and shaft rotors have several advantages(as compared to conventional tilting pad bearings using babbit orpolymer pad surfaces with steel runners). For example, PCD tilting padsand PCD rotors exhibit less wear due to the inherent wear resistance ofPCD. Wear in tilting pad bearings normally occurs during starting andstopping of the machine rotating parts. Additionally, a bearing thatplaces one PCD bearing surface against another bearing PCD surface tendsto not gall or wipe as typical metal bearing surfaces. Rather, suchsurfaces tend to polish with the result of improving the bearing surfacecharacteristics. It is also believed that, with an exceptionally highthermal conductivity, PCD bearing pads should also remove more heat fromthe bearing surface which may, in turn, increase the viscosity of thefluid and increase the film thickness during hydrodynamic operation—animportant parameter in tilting pad bearing performance and design. Thehigh thermal conductivity will also remove heat from the contactingsurfaces during starting and stopping, which will help to keep thecontacting surfaces from overheating. As noted above, and as will beappreciated by those of ordinary skill in the art, bearing surfaces in atilting pad design may conventionally be separated by a fluid filmduring normal operation so that surface wear and frictional forces aresubstantially reduced. Among other things, the fluid film helps todistribute forces among the pads or shoes of the bearing assembly.Additionally, such a bearing configuration provides superior shockabsorbing and damping characteristics.

While specific examples of bearing elements, bearing assemblies andmanufacturing processes are described herein, a variety of othertechniques, features and processes may be utilized in association withthe described embodiments. For example, various types of bearingelements are described in U.S. Pat. Nos. 7,635,035, 7,866,418 and8,146,687, as well as in U.S. patent application Ser. Nos. 11/545,929,12/495,986, 13/070,636 and 13/087,775, the disclosures of each of whichare incorporated by reference herein in their entireties. Additionally,various bearing ring designs and manufacturing processes are describedin U.S. Pat. Nos. 7,533,739, 7,901,137 and 7,942,218 as well as in U.S.patent application Ser. Nos. 12/425,304 and 12/761,535, the disclosuresof each of which are incorporated by reference herein in theirentireties.

Referring to FIGS. 1A-1C, various views are shown of a bearing assembly100 in accordance with an embodiment of the present invention. In thepresently described embodiment, the bearing assembly 100 is configuredas a thrust bearing. However, as will become apparent below, variousfeatures and aspects of the present invention are applicable to a numberof other types of bearings as well.

The bearing assembly 100 includes a pair of tilting pad assemblies 102Aand 102B with a bearing runner 104 disposed therebetween. While thetilting pad assemblies 102A and 102B may be configured differently fromeach other, in the present embodiment they are configured to besubstantially identical to one another. As such, similar (although,perhaps not identical) components in the tilting pad assemblies 102A and102B will be identified with common references numerals.

The tilting pad assemblies 102A and 102B each include a body 106configured in a generally ring-shaped or toroid-shaped configuration andmay define an aperture 108 which may be generally centered about alongitudinal axis 110. An annulus 112 or an annular channel may beformed in the body 106 to house some of the components of the padassembly 102. For example, a plurality of components that form aleveling mechanism 114 as will be described in further detail below. Aplurality of individual bearing elements, also referred to as tiltingbearing pads 116 (or tilting shoes), are positioned above the levelingmechanism and may be partially disposed in the annulus 112 of the body106.

Referring to FIGS. 2A and 2B in conjunction with FIGS. 1A-1C, eachtilting bearing pad 116 may be formed to include one or morepolycrystalline diamond (PCD) layers 118 formed on a base layer 120. ThePCD layer 118 may include a substrate 122 and a diamond table 124 andmay be formed, for example, using high-temperature, high-pressuresintering processes such as set forth above. In one particularembodiment, the substrate 122 may comprise tungsten carbide, althoughother materials may be utilized. In other embodiments, the substrate 122may be optionally omitted. The base layer 120 of the tilting bearing pad116 may be formed of a variety of materials including, for examplevarious metals, metal alloys or carbide materials. In one example, thebase layer 120 may comprise a steel material. In another example, thebase layer 120 may comprise a tungsten carbide material (e.g., acemented tungsten carbide material, such as, for example, cobalt-cementstungsten carbide). The use of a tungsten carbide material to form boththe base layer 120 and the substrate of the PCD layer 118 may help toreduce or eliminate residual stresses in the tilting pad bearing pad 116after fabrication due to fact that such components would exhibitsuitably similar rates of thermal expansion. In other embodiments, aswill be described below, a material with a relatively higher rate ofthermal expansion may be used for the base layer 120 in order to corrector take advantage of any warping tin the PCD layer 118 during brazing.

In one embodiment, the PCD layer 118 may be formed as a PCD compact(e.g., a 19 millimeter or a 13 millimeter diameter PCD compact) that isshaped, such as by machining or otherwise shaping the sides (e.g.,grinding or wire electro discharge machining), to a desired geometry.For example, a conventional round-shaped PCD compact (represented bydashed lines in FIG. 2A) may cut or machined to exhibit a substantiallywedge- or annular sector-shaped geometry as shown in FIG. 2A).

The tilting pad bearings 116 also include a protrusion or button 126along a portion of the base layer 120. The button 126 engages a portionof the leveling mechanism 114 and enables the tilting pad bearing 116 totilt, pivot or rock relative to the leveling mechanism 114 as well asthe body 106 within a defined range of motion. For example, as seen inFIG. 1C, the button 126 may be configured to abut a portion of theleveling mechanism 114 such that there is a gap or a space between thebase layer 120 of the tilting pad bearing 116 and the adjacentcomponents of the leveling mechanism 114 (as well as between the baselayer 120 of the tilting pad bearing 116 and adjacent portions of thebody 106) so that the tilting pad bearing 116 can rock relative to suchcomponents. In one example, such as illustrated by FIG. 2B, the button126 is substantially centered relative to the radial edges of thetilting pad bearing 116. However, in other embodiments, such as shown inFIG. 2C, the button 126 may be slightly off center relative to theradial edges of the tilting pad bearing 116. In one particularembodiment, the center of the button 126 may be placed at a locationthat is approximately 60% of circumferential distance away from theleading edge of the tilting pad bearing 116 (the circumferentialdistance being shown as length L extending from one radial edge to theother radial edge). The button 126 may also be centered between innerand outer circumferential edges, or it may be displaced toward one ofthe circumferential edges if desired.

Referring to FIGS. 3A and 3B, another embodiment of a tilting padbearing 116 is illustrated. As with the embodiments described withrespect to FIGS. 2A-2C, each tilting bearing pad 116 may be formed toinclude one or more polycrystalline diamond (PCD) layers 118 formed on abase layer 120. The PCD layer 118 may include a substrate 122 and adiamond table 124 and may be formed, for example, usinghigh-temperature, high-pressure sintering processes such as set forthabove. In one particular embodiment, the substrate 122 may comprisetungsten carbide, although other materials may be utilized. In otherembodiments, the substrate 122 may be optionally omitted or thesubstrate 122 may form the portion shown as base layer 120 (i.e., baselayer 120 may be optionally omitted). The base layer 120 of the tiltingbearing pad 116 may be formed of a variety of materials including, forexample various metals, metal alloys or carbide materials. In oneexample, the base layer 120 may comprise a steel material. In anotherexample, the base layer 120 may comprise a tungsten carbide material(e.g., a cemented tungsten carbide material, such as, for example,cobalt-cemented tungsten carbide). The tilting pad 116 bearing may beformed from substantially similar materials, and using substantiallysimilar processes, as those described with respect to other embodimentsdescribed above. However, it is noted that the tilting pad 116 exhibitsa substantially cylindrical geometry rather than being shaped like someother embodiments described herein. Thus, the tilting pad 116 may beformed from, for example, a conventional PCD compact, such as a 13 mm ora 19 mm diameter compact. Of course, the tilting pad 116 may exhibitother sizes, or may be cut from a tool blank or otherwise formed ifdesired.

The tilting pad bearings 116 may also include a protrusion or button 126along a portion of the base layer 120. As shown in FIG. 3B, the button126 may be integrally formed with, for example, the base layer 120. Inother embodiments, the button 126 may be a separate component adhered,coupled or affixed to, for example, the base layer 120. As seen in FIG.3C, in another embodiment, a lower surface of the base layer 120 may berounded to exhibit a substantially spherical (or a portion of a sphere)to act as the button 126.

Referring briefly to FIG. 4, an example is shown of the tilting padbearings 116 disposed on components of the leveling mechanism 114 withthe body 106 and other components of the tilting pad bearing assembly102A (or 102B) being absent in order to provide a better view of theleveling mechanism 114. The leveling mechanism 114 includes a pluralityof lower components 127A and a plurality of upper components 127B thatengage one another in a generally conformal or mating relationship, withupper and lower components alternating as they circumferentially extendabout the annulus 112 in which they are disposed (see e.g., FIG. 1C). Itis noted that the terms “upper” and “lower” are used for convenience andare used as relative terms with respect to the view shown in FIG. 4. Thebuttons 126 of the tilting pad bearings 116 each rest on a correspondingupper component 127B and may tilt or rock relative thereto. In someembodiments, the leveling mechanism 114 may be omitted.

Referring back to FIGS. 1A-1C, the body 106 may be configured to limitthe movement of the tilting pad bearings 116 in various directions(within defined limits or tolerances) relative to the body 106. Forexample, notches or recesses 128 may be formed in the body 106 to engageshoulder portions or other surfaces of the tilting pad bearings 116. Therecesses 128 help to maintain the tilting bearing pads 116 at a desiredposition relative to the body 106 and limit the tilting pad bearings 116from moving in a circumferential direction relative to the body 106during operation of the assembly 100.

When assembled, retaining devices 130 such as fasteners (or otherstructures or mechanisms) may be associated with the body 106 to engagea portion of the leveling mechanism 114 (e.g., a slot 131 or otherfeature in, for example, the upper components 127B) to retain theleveling mechanism in a desired position (within desired tolerances orspecifications) within the annulus 112 (e.g., see FIG. 1C). Anotherplurality of retaining devices 132 such as fasteners (or otherstructures or mechanisms) may also be associated with the body 106. Inone embodiment, the retaining devices 132 include fasteners locatedalong a face that is generally opposite the face where the tilting padbearings 116 are located. Each retaining device 132 may engage a portionof the leveling mechanism 114 (e.g., a lower component 127A) to preventthe leveling mechanism 114 from moving in the circumferential direction,or at least limit its circumferential movement within desired tolerancesor specifications. The use of a leveling mechanism 114 may helpcompensate for differences in manufacturing tolerances of the numerouscomponents that make up the bearing assembly 100.

Still referring to FIGS. 1A-1C, the runner 104 of the bearing assemblyincludes a base layer 140, a first PCD layer 142A on the base layerforming a first bearing face 144A, and a second PCD layer 142B on thebase layer 140 forming a second bearing face 144B or surface, the twobearing faces being on opposite sides of the base layer 140. Each of thePCD layers 142A and 142B may include a substrate 146 and a diamond table148 and may be formed, for example, using high-temperature,high-pressure sintering processes. In one particular embodiment, thesubstrate 146 may comprise tungsten carbide, although other materialsmay be utilized. The base layer 140 of the runner 104 may be formed of avariety of materials including, for example various metals, metal alloysor carbide materials. In one example, the base layer 140 may comprise asteel material. In another example, the base layer 140 may comprise atungsten carbide material.

As perhaps best seen in FIG. 1B, the runner 104 may be configured as asubstantially annular or ring shaped body defining an opening 150 whichmay be generally centered about a longitudinal axis 110. A recess 152may be formed, for example, in an inner surface of the runner thatdefines the opening 150. The recess 152 may be configured as a keyway toenable coupling of the runner 104 to a shaft (not shown) or otherstructure extending through the various openings 108 and 150. Thecoupling of the runner 104 with a shaft or other structure will helpenable relative rotation of the runner 104 and the tilting bearing padassemblies 102A and 102B.

The runner 104 is disposed between the tilting pad assemblies 102A and102B such that the first bearing face 144A engages the collectivebearing surface 134A of one tilting pad bearing assembly 102A and thesecond bearing face 144B engages the collective bearing surface 134B ofthe other tilting pad bearing assembly 102B. As noted above, the bearingassembly 100 is configured so that a shaft may pass through the openingsand, for example, be coupled with the runner 104 and be rotated aboutthe longitudinal axis relative to the tilting pad bearing assemblies102A and 102B. In this configuration, the runner 104 may be considered arotor while the tilting pad assemblies 102A and 102B may remain in asubstantially fixed position relative to the runner 104 and beconsidered to be stators. In other embodiments, the runner 104 may beconfigured as a stator while the tilting bearing pad assemblies 102A and102B may be configured as rotors. Other potential embodiments are alsoconsidered, including any or all of tilting bearing pad assemblies 102Aand 102B and the runner 104 being configured to rotate, but at differentrotational rates, or in different directions, relative to adjacentcomponents or assemblies.

It is noted that implementing PCD materials into tilting pad geometriespose various challenges. For example, forming relatively large bearingsurfaces (e.g., the bearing surface of a tilting pad bearing 116 or thebearing face 144A of a runner 104) can be challenging due toconventional PCD manufacturing processes. For example, a tilting padbearing 116 may be sized to be less than an inch in length and/or widthin one embodiment and may be as large as a few feet in length and/orwidth in another embodiment. If the tilting pad bearing 116 is toexhibit a bearing surface that is substantially similar to the size of aconventional PCD compact, then a single PCD compact may be used to formthe bearing pad 116. However, when the tilting pad bearing 116, or thebearing face of the runner 104, is larger than a conventional PCDcompact, then other approaches need to be utilized.

Referring briefly to FIG. 5A, a tilting pad bearing 116 is shown inaccordance with one embodiment of the present invention. The tilting padbearing 116 includes a PCD material layer 118 and a base layer 120. ThePCD layer 118 includes a PCD table 124 formed on a substrate 122 such asdescribed above. The PCD layer 118 is formed from a plurality ofindividual PCD compacts that have been cut or formed into a desiredshaped segments (e.g., square or rectangular) and placed together toform the PCD layer 118. For example, in an assembly 100 that exhibits anouter diameter of roughly 11 inches, the surface of the tilting bearingpad 116 may be 2 inches in length and in width or greater. Thus, severalPCD compacts (PDCs) exhibiting, for example, a ¾ inch diameter may becut (e.g., using a laser or an electro discharge machine (EDM) process)into individual squares, rectangles or other desired shapes 160. The cutshapes 160 may then be fitted together on the base layer 120 and bondedtherewith.

In another embodiment, referring to FIG. 5B, the PCD layer 118 may beformed as a single, integral component. For example, the PCD layer 118may be cut from a PCD cutting-tool blank that exhibits a sufficientlylarge size. In one example, a PCD cutting-tool blank having a diameterof approximately 2 to 3 inches may be cut (e.g., using laser, grinding,and/or EDM processes) to the desired shape of the tilting pad bearing116.

It is noted that the tilting pad bearings 116 shown in FIGS. 5A and 5B(as well as in FIGS. 1A-1C) are shown to include a bearing surface thatmay be generally described as being an annular sector (i.e., acircumferential portion of a ring), having an inner radius and an outerradius that are connected by two spaced-apart, radially extending edges.As seen in FIG. 5B, the corners joining the various sides may be roundedor clipped. Additionally, as seen in FIGS. 5A and 5B, the peripheraledge of the upper surface may exhibit a chamfer or a radius if desiredto prevent a sharp edge from potentially chipping or breaking as itengages other surfaces during operation of the bearing assembly 100.However, such a configuration for the tilting pad bearings 116 is merelyan example and should not be considered limiting. Other shapes andconfigurations are also contemplated. For example, in anotherembodiment, the bearing surface presented by the tilting pad bearing 116may be substantially circular rather than an annular sector. Such aconfiguration, depending on the size of the tilting pad bearing 116, maybe more amenable to using PCD compacts (or PCD cutting-tool blanks) andmay result in less waste since less (or perhaps none) of the PCD compactwill have to be trimmed before or after attaching it to the base layer120 of the tilting pad bearing 116.

Referring to FIG. 6A, a runner 104 is shown in accordance with anembodiment of the present invention. The PCD layers 142A and 142B of therunner 104 may be configured of a plurality of cut shapes 162, such assquares, rectangles or other shapes (or combinations thereof) formedfrom individual PCD compacts, similar to the PCD layer 118 of thetilting pad bearing 116 described with respect to FIG. 5A above. Inanother embodiment, as seen in FIG. 6B, PCD layers 142A and 142B of therunner 104 may be configured of a plurality of annular sector shapes164, similar to the PCD layers 118 of the tilting pad bearing 116described with respect to FIG. 5B above. Indeed, in one embodiment, theannular sector shapes 164 may be manufactured to be substantiallyidentical to the PCD layers 118 of the tilting pad bearings 116, whichmay reduce manufacturing costs and complexities.

Referring to FIGS. 7A and 7B, a runner 104 and a base layer for therunner 104 are shown, respectively, in accordance with anotherembodiment of the present invention. The PCD layers 142A and 142B of therunner 104 may be configured of a plurality of annular sector shapes164, as with the embodiment illustrated in FIG. 6B. The base layer 140may include a plurality of alignment features 168 circumferentiallyspaced along each axial face of the runner so as to sit between andcircumferentially align adjacent annular sector shapes 164 of the PCDlayers 142A and 142B. Additionally, the base layer may includeshouldered portion 168 on each face (only one shown in FIGS. 7A and 7B)about the radially inner periphery to abut and radially align theannular sector shapes 164 of the PCD layers 142A and 142B. Of courseother features and techniques may be used to align the variouscomponents and such alignment features 166 and 168 are merely examplesthat may be used in various embodiments. In the embodiments describedwith respect to FIGS. 6A, 6B, 7A and 7B, the PCD layers 142A and 142Bmay be attached to the base layer 140 substantially simultaneouslyusing, for example, a brazing process. In other embodiments, each layermay be attached to the base layer in an independent process.

Referring to FIGS. 8A and 8B, another embodiment of a runner 104 isillustrated. As with previously described embodiments, the PCD layers142A and 142B of the runner 104 may be configured of a plurality ofindividual PCD components (showing, again, an annular sector 164 thatmay be formed from a conventional PCD compact or from a toolingblank—represented in dashed lines). While FIGS. 8A and 8B depict the PCDlayers 142A and 142B as being formed using annular sectors 164, othershapes may also be utilized such as described above. The base layer ofthe runner 104 may be formed from multiple components including, forexample, a first base component 140A associated with the first PCD layer142A and a second base component 140B associated with the second PCDlayer 142B. The base components 140A and 140B may be coupled to oneanother, for example, by way of a plurality of fasteners 170. The basecomponents may be keyed or otherwise cooperatively shaped to ensurealignment with one another upon assembly. In another embodiment, thefinal shaping and finishing of the runner 104 may be accomplished afterthe assembly of the various components.

Referring to FIG. 8C, an enlarged, cross-sectional view a PCD component(e.g., a PCD compact shaped for use as an annular sector 164 of a PCDlayer 142A or 142B) is shown. Base members 172 may be brazed orotherwise attached to the PCD compact and configured for coupling with afastener 174 (see FIG. 8B) to fasten the annular sector 164 (orother-shaped PCD component) to a base component 140A or 140B of therunner 104. While only one base member is shown as being brazed to theannular sector 164 in FIGS. 8B and 8C, multiple of such members may bebrazed to each annular sector 164. For example, in one particularembodiment, three distinct base members 172 may be brazed on to theannular sector 164. In other embodiments, a single, larger base memberthat is substantially similar in geometry to the annular sector (e.g.,also exhibiting an annular sector geometry) may be brazed to the annularsector and have threaded holes tapped in for subsequent coupling with anassociated base component 140A or 140B. Thus, assembly of the runner 104may be accomplished with minimal brazing (e.g., the base members 172)while other components may be assembled using other coupling orattaching techniques. In other embodiments, the PCD components of thePCD layers 142A and 142B (e.g., the annular sectors) may be brazed totheir associated base components 140A and 140B with the base componentsbeing subsequently assembled using, for example, fasteners or othermechanical components.

Referring now to FIGS. 9A-9D another embodiment of a runner 104 isillustrated. As with previously described embodiments, the PCD layers142A and 142B of the runner 104 may be configured of a plurality ofindividual PCD components. While the embodiment illustrated by FIGS.9A-9D depict the PCD layers 142A and 142B as being formed using annularsectors 164, other shapes may also be utilized such as has beendescribed above. Each PCD layer 142A and 142B is associated with a basering member 140A and 140B. The base ring members 140A and 140B may beformed, for example, of steel or of any other material suitable forattaching the annular sectors 164 of the PCD layers 142A and 142B. Inone embodiment, the annular sectors 164 may be brazed to the base ringmembers 140A and 140B.

A central base component 140C may be formed, for example, of steel oranother appropriate material. Annular grooves 175A and 175B are formedon each axial face of the central base component 140C. As seen best inFIG. 9B, the base ring members 140A and 140B are each positioned withinan associated annular groove 175A and 175B of the central base component140C. In one embodiment, the base ring members 140A and 140B may besecured to the central base component 140C by way of an interference fit(such as a press fit) with their associated annular grooves 175A and175B.

Referring briefly to FIG. 10A, a top view of another embodiment of atilting pad bearing 116 is shown. The tilting pad bearing 116 exhibits asubstantially annular sector shape, such as has been described above,and includes a base layer 120 with a plurality of PCD elements 176(e.g., polycrystalline diamond compacts) coupled with the base layer toform a PCD layer 118 as a bearing surface. It is noted that theplurality of PCD elements 176 are not cut, formed or otherwise shaped sothat they fit tightly next to each to form a substantially continuousbearing surface (such as with the embodiment shown in FIG. 5A). Rather,the PCD elements 176 are generally circular in shape and there are gapsbetween adjacent PCD elements 176 on a given tilting pad bearing 116. Itis noted that, while such a configuration may not perform as anidealized hydrodynamic bearing, such may provide a lower costalternative to other embodiments by enabling the use of conventional,prefabricated PCD compacts without substantial modification (e.g.,through subsequent cutting or forming operations using laser or EDMprocesses) and by using fewer compacts to form the bearing surface.Additionally, such a configuration should provide increased cooling byvirtue of the spaces between the individual PCD elements 176. Theindividual PCD elements 176 may be arranged according to a particulardesign or geometry or may be spaced so that they exhibit a specificdistances with adjacent PCD elements 176. As shown in FIG. 10B, anotherembodiment may include a tilting pad bearing 116 that exhibits asubstantially round geometry (viewed from above as with FIG. 10A) orsome other geometry instead of an annular sector. The tilting padbearing 116 shown in FIG. 10B includes a base layer 120 with a pluralityof PCD elements 176 coupled with the base layer to form a PCD layer 118as a bearing surface similar to that which is described with respect tothe embodiment shown in FIG. 10A.

Referring briefly to FIG. 11, a runner 104 is shown that includes a baselayer 140 and a plurality of PCD elements 178 (such as polycrystallinediamond compacts) coupled with the base layer 140 to form a PCD layer(e.g., 142A or 142B). The PCD elements 178 are arranged in a similarmanner as discussed with respect to the tilting pad bearings 116 shownin FIGS. 10A and 10B, being generally circular in cross-sectionalgeometry and being spaced apart from one another such that there aregaps or spaces between adjacent PCD elements 178. The individual PCDelements 178 may be arranged according to a particular design orgeometry or may be spaced so that they exhibit a specific distances fromadjacent PCD elements 178. It is noted that different embodiments of therunner 104 may be combined with different embodiments of the tilting padbearings 116. For example, the runner 104 shown and described withrespect to FIG. 11 may be combined in an assembly that includes tiltingpad bearings shown and described with respect to FIG. 5A or 5B. Ofcourse other combinations of embodiments are also contemplated, withoutlimitation.

Referring briefly to FIG. 12, another embodiment of a runner 104 isshown. The runner 104 includes a base layer 140 and a plurality of PCDelements 179 (such as polycrystalline diamond compacts) coupled with thebase layer 140 to form a PCD layer (e.g., 142A or 142B). The PCDelements 179 shown in FIG. 12 are arranged in two circular rows,although a single row may be used or more rows than two may be employed.The PCD elements 179 may be formed from a cylindrical PCD compact, suchas described above and as indicated again by dashed lines about one ofthe PCD elements 179. Such PCD compacts may be trimmed to exhibit asubstantially wedge-shaped or annular sector-shaped geometry so as tofit the various PCD elements 179 into a circular pattern with relativelysmall gaps, or even substantially no gaps, being present betweenadjacent PCD elements 179.

Attaching the PCD layer to the base material (for either the tilting padbearings 116 or the runner in 104 any of the various embodimentscontemplated herein) may be accomplished a variety of processes such as,for example, by brazing, by e-beam welding, mechanical attachment or anyother suitable configuration. In any case, attaching the PCD layer tothe base material can provide certain challenges.

Referring to FIGS. 13A-13E, some examples of techniques for attachingthe PCD layer to a base material are illustrated.

With initial reference to FIG. 13A, a bearing element 180 (which may beused as a tilting pad bearing or as a runner) may be formed by providinga base layer 182 and forming a pocket 184 in the base layer 182. A PCDelement 186 (e.g., a polycrystalline diamond compact that includes adiamond table 188 formed on a substrate 190) may be disposed in thepocket 184. The PCD element 186 may then be joined (e.g., brazed) to thebase layer 182 to fix it relative to the base layer 182. The base layer182 and the PCD element 186 may be held in place during joining by useof proper fixtures and/or by appropriate application of force to thecomponents of the bearing element 180. As previously mentioned, the baselayer 182 and the substrate may be formed of substantially similar orsuitable materials or of materials that exhibit suitable coefficients ofthermal expansion to help reduce or prevent cracking or the induction ofthermal stresses into the resulting bearing element 180. While a singlepocket 184 is shown in the base layer 182, multiple pockets may beformed with a PCD element 186 being disposed in each pocket if desired.The pocket 184 may be shaped to correspond with the cross-sectionalgeometry of the compact 186. Thus, for example, if the PCD element 186is substantially cylindrical in shape, the pocket 184 may besubstantially cylindrically shaped to receive the compact therein in asubstantially mating relationship.

Referring to FIG. 13B, a bearing element 180 may be formed in accordancewith another embodiment by providing a pocket 184 in a base layer 182and disposing a plurality of PCD elements 186 within the pocket 182. Inone embodiment, the PCD elements 186 may be abutted against each otherso that they are in contact with each other and exhibit little or nospace therebetween. The PCD elements 186 may exhibit a variety of shapesand, in one embodiment, may be configured as squares or rectangles thatare combined together to provide, for example, a bearing surface similarto that described with respect to the tilting pad bearing shown in FIG.5A.

The use of a pocket to effect the joining of the base layer 182 and thePCD element 186 will help to maintain alignment of the components duringany heating that may take place in the joining process. The PCD elements186 may be joined with the base layer 182, such as by brazing, whilethey are held in position within the pocket 184 by an applied force orby appropriate fixtures. The pocket 184 may be shaped to correspond withthe combined cross-sectional geometry of the plurality of PCD elements186. Thus, for example, the plurality of compacts 186 may be shaped andcombined to define a substantially annular sector shape, with the pocketbeing similarly shaped to receive such a combination of PCD elements186. Of course, other geometries and configurations are alsocontemplated. Once secured to the base layer 182, the PCD elements 186may be machined, ground or lapped to provide a substantially coplanarsurface (i.e., within defined tolerances) for the resulting bearingelement 118.

It is noted that, while the embodiments shown and described with respectto FIGS. 13A and 13B are described in terms of joining the PCD elements186 with the base material 182 through processes such as brazing, othermeans of attaching or coupling may also be used. In one example, thepockets 184 and the compacts 186 may be configured to effect aninterference fit (i.e., a press fit or a shrink fit). For example, thepocket 184 may be configured to be slightly smaller than the PCD compact186 that is to be disposed therein. The base layer 182 may then beheated to make it expand and/or the PCD element(s) 186 may be cooled tomake it (them) contract prior to disposing the PCD element(s) 186 in thepocket 184. After placing the PCD elements(s) 186 in the pocket 184,which may require application of force, the two components may bebrought to a common temperature causing the pocket 184 to “shrink”and/or the PCD element 186 to expand resulting in the PCD element 186being tightly grasped by the pocket 184 of the base layer 182.

Referring briefly to FIG. 13C, in another embodiment, a bearing element180 may be formed by placing a base layer 182 and the PCD element 186 ina fixture 192 and holding the components in alignment during brazing. Insuch a configuration, it is not necessarily required to have a pocketformed in the base layer 182. Rather, the PCD element 186 may be simplyabutted against a surface of the base layer 182 and maintained in thatposition by the fixture 192. For example, the fixture 192 may beconfigured to hold the sidewalls of the compact 186 in alignment withthe side walls of the base layer 182 while a brazing, bonding or someother joining process takes place.

Referring to FIG. 13D, in accordance with another embodiment, a bearingelement 180 may be formed by placing a PCD elements 186 on a base layer182 and joining them together, such as by brazing. The PCD element 186and/or the base layer 182 may be originally formed as an “oversized”component, meaning that it is larger than its final design dimensions.The excess of the base layer 182 and/or the PCD element 186 may be cutor machined to final dimensions as indicated by dotted lines 194 suchthat it looks as shown in FIG. 13E. Such a process should eliminate someconcerns of alignment between the PCD element 186 and the base layer 182during the joining process. Referring specifically to FIG. 13E, such abearing element may also be formed by aligning the compact 186 with asimilarly sized base layer 182 and E-beam welding the two componentstogether. E-beam welding may involve less heating of the base material182 and compact 186 and may result in less residual stress and warpingof such components.

Referring to FIGS. 14A and 14B, another embodiment of a bearing element200 is shown. The bearing element 200 includes a first base layer 202which is pre-brazed to a PCD element 204. The PCD element 204 mayinclude a diamond table 206 bonded to a substrate 208 such as has beendescribed hereinabove. The first base layer 202 may be formed, forexample, of steel, another metal, or a metal alloy. A threaded hole 210may be formed in the first base layer. As seen in FIG. 14B, a pluralityof bearing elements 200 may be positioned adjacent each other andcoupled with a second base layer 212. The second base layer 212 mayinclude a plurality of through holes 214 that align with the holes 210of individual bearing elements 200 and threaded fasteners 216 may beused to couple the second base layer 212 with the individual bearingelements 200. As with previously described embodiments, the bearingelements 200 may be formed to exhibit various shapes and sizes. Forexample, in one embodiment, the bearing elements 200 may besubstantially cylindrical. In another embodiment, they may be configuredto exhibit a square, rectangular or other polygonal shape. They may bespaced apart (e.g., such as shown with respect to FIG. 10A, 10B or 11)or they may be placed adjacent to each other and fit together to form asubstantially continuous surface (e.g., such as shown in FIG. 5A, 6A or6B). Also, as with other embodiments, after assembly of the bearingelements 200 with the second base layer 212, the bearing elements may bemachined, ground, lapped or otherwise processed to obtain substantiallycoplanar bearing surfaces.

Referring to FIGS. 15A-15C, another embodiment of a bearing element 230is shown. FIGS. 15A and 15B depict a PCD element 232 having a diamondlayer 234 bonded with a substrate 236. A pair of shoulders 238 areformed in the PCD element 232 at diametrically opposing sides. As shownin FIG. 15C, the PCD element 232 is placed on a base layer 240 which hasa plurality of threaded blind holes 242 formed therein. Clamps 244 maybe coupled to the base layer 240 by way of threaded fasteners 246. Theclamps 244 include an extension or projection 246 that engages ashoulder 238 of the PCD element 230 to hold the element 230 securelyagainst the base layer 240. It is noted that the shoulders formed in thePCD element 232 need not be two in number, or necessarily diametricallyopposed in location. Rather, other quantities and arrangements ofshoulders, tapered geometries, or other suitable engagement features arecontemplated. In one embodiment, a shoulder may be formed about theentire periphery of the compact 232 so that alignment issues withrespect to the clamp locations are negated. Also, any number of clamps246 may be utilized, including a single ring clamp that extends about atleast a portion of the periphery of the compact 232.

Referring to FIGS. 16A-16D, another embodiment is shown for attaching aPCD element 260 to a base member 262. FIGS. 16A and 16B show a basemember 262 that includes a recessed surface 264 exhibiting an arcuatesurface. For example, the recessed surface 264 may exhibit asubstantially spherical geometry (such as a portion of a sphere). FIG.16C shows a PCD element 260 being attached to the base member 262 by wayof a layer of brazing material 266. The PCD element 262 and brazingmaterial 266 may substantially conform to the recessed surface 264 ofthe base member 262 while such materials are at elevated temperaturesduring the brazing process. However, due to the pairing of materialsbased on coefficients of thermal expansion (e.g., selecting materialswith a desired differential in their respective coefficients of thermalexpansion), the base member 262 may warp or deform upon cooling toatmospheric temperatures from the elevated brazing process temperatures.The PCD element 260 now exhibits a substantially flat or planar surfacewhile the bottom or lower surface of base member 262 may be arcuate ornon-planar.

Following the manufacture of the bearing elements, regardless of themanufacturing process used, the bearing elements may be incorporatedinto an assembly to form, for example, a bearing surface on a runner ora collective bearing surface in a tilting pad bearing assembly. Again,the bearing surfaces of such assemblies may be lapped, machined orground to defined a substantially coplanar bearing surface.

Referring now to FIG. 17 a radial bearing assembly 300 is shown. In oneembodiment, the bearing assembly 300 includes a first bearing 302configured as a rotor and a second bearing ring 304 configured as astator. In other embodiments, the first bearing ring 302 may beconfigured as a stator and the second bearing ring 304 may be configuredas a rotor. The second bearing ring 304 defines an opening 306 that issubstantially centered about an axis 308 and the first bearing ring 304extends through the opening 306. Whichever bearing ring is configured asa rotor is configured to rotate generally about the axis 308.

Referring to FIGS. 18A-18C, the second bearing ring 304 includes a body310 having an outer radial surface 312 and an inner radial surface 314that defines, in large part, the opening 306. A plurality of tilting padbearings 316 are positioned against the inner radial surface 314 atcircumferentially spaced locations. The tilting pad bearings 316 may beheld in place within the body 310 by a pair of plates 318 coupled withopposing axial sides of the body 310. As best seen in FIG. 18C, eachtilting pad bearing 316 includes a diamond layer 320 (or othersuperabrasive layer) attached to a base layer 322. The diamond layer mayinclude a plurality of PCD elements 326 disposed next to each other andcollectively defining a substantially arcuate surface 328. The PCDelements 326 may each be configured to include a diamond table and asubstrate such as has been described hereinabove. The plurality oftilting pad bearings 316 collectively define a bearing surface whichengages a bearing surface 330 of the first bearing ring 302, separatedby a fluid film which may develop into a fluid film wedge 331 duringrelative rotation of the first bearing ring 302 and the second bearingring 304 as will be appreciated as will be appreciated by those ofordinary skill in the art. In one embodiment, it is noted that the baselayer 322 of the tilting pad bearings 316 exhibits a radius that issmaller than the radius of the inner radial surface 314 of the body suchthat the tilting pad bearings 316 may rock relative to the body 310.

As seen in FIGS. 19A and 19B, in one embodiment the bearing elements 326may be configured to exhibit a substantially trapezoidal cross-sectionalgeometry with a narrower upper portion (i.e., across the upper surfaceof the diamond layer 356) and a wider lower portion (i.e., across thelower surface of the substrate 354). Such a configuration enables aplurality of bearing elements 326 to be arranged with sidewalls 358 ofone bearing element 326 being positionable adjacent the sidewalls 358 ofother bearing elements 326 such that the diamond layers of the pluralityof bearing elements 326 collectively define a portion of a substantiallycylindrical bearing surface. In one embodiment, the upper surface of theindividual bearing elements 326 may be arcuate (i.e., concave, as shown)to define a portion of a cylindrical bearing surface. The arcuateprofile may be machined on each PCD compact individually prior toassembly or the entire assembly may be machined to define the arcuatebearing surface after the bearing elements 326 are otherwise assembled.In another embodiment, the upper surface of each bearing element 326 maybe substantially planar such that the resulting bearing surface is (atleast initially, prior to wear) approximated as a portion of acylindrical surface. In one embodiment, one or more chamfers 360 may beformed between the upper surface of the diamond layer 356 and a sidewall 358 of the bearing element 326, as indicated in FIG. 19A by dashedlines. In other embodiments, other edge treatments may be used, such asthe forming of a radius between the upper surface of the diamond layer356 and a side wall 358 of the bearing element. In other embodiments,one or more chamfers may be combined with one or more radii along thetransition edge of two such surfaces.

Referring briefly to FIG. 20, in one embodiment, PCD elements 326 (orother PCD elements such as PCD elements 352 described with respect toFIGS. 22A and 22B below) may be formed from a PCD cutting tool blank340. In one particular example, a cutting tool blank 340 having adiameter of approximately 2.36 inches may be cut into six individual PCDelements 326 and 352 each having a length of approximately 1.6 inchesand a width of approximately 0.3 inch. Of course other sizes andgeometries are contemplated and such an example should not be consideredlimiting.

Referring to FIGS. 21A and 21B, the first bearing ring 302 includes abody portion 350 that serves as a base layer and a plurality of bearingelements 352 coupled with the body portion 350 to define the bearingsurface 330 of the first bearing ring 302. Each of the bearing elements352 may be configured as PCD elements including a substrate 354 and adiamond layer 356 such as has been previously described. As seen inFIGS. 22A and 22B, in one embodiment the bearing elements 352 may beconfigured to exhibit a substantially trapezoidal cross-sectionalgeometry with a wider upper portion (i.e., across the upper surface ofthe diamond layer 356) and a narrower lower portion (i.e., across thelower surface of the substrate 352). Such a configuration enables aplurality of bearing elements 352 to be arranged with the sidewalls 358of one bearing element 352 being positioned adjacent the sidewalls 358of other bearing elements 352 such that the diamond layers of theplurality of bearing elements 352 collectively define a substantiallycylindrical bearing surface 330 (FIG. 21A).

In one embodiment, the upper surface of the individual bearing elements352 may be arcuate (i.e., convex, as shown) to define the cylindricalbearing surface 330. The arcuate profile may be machined on each PCDcompact individually prior to assembly or the entire assembly may bemachined to define the arcuate bearing surface 330 after the bearingelements 352 otherwise assembled. In another embodiment, the uppersurface of each bearing element 352 may be substantially planar suchthat the resulting bearing surface 330 is (at least initially, prior towear) approximated as a cylindrical surface. In one embodiment, one ormore chamfers 360 may be formed between the upper surface of the diamondlayer 356 and a side wall 358 of the bearing element 352, as indicatedin FIG. 22A by dashed lines. In other embodiments, other edge treatmentsmay be used, such as the forming of a radius between the upper surfaceof the diamond layer 356 and a side wall 358 of the bearing element. Inother embodiments, one or more chamfers may be combined with one or moreradii along the transition edge of two such surfaces.

Referring now to FIGS. 23A and 23B, a tilting pad bearing 316 for use inthe second bearing ring 304 is shown in accordance with anotherembodiment. The tilting pad bearing 316 includes a base layer 322 and aplurality of PCD elements 326. The PCD elements 326 may each beconfigured to include a diamond table and a substrate such as has beendescribed hereinabove. However, rather than exhibiting a geometry thatis elongated with a substantially square or rectangular cross-section(with an optional arcuate bearing) such as described with respect to theembodiment shown in FIGS. 18A-18C, the PCD elements 326 aresubstantially cylindrical and arranged in an array of rows and columnsto define a collective bearing surface. In one embodiment, such PCDelements 326 may comprise conventional PCD compacts which aresubsequently attached to the base layer 322 (e.g., by brazing or otherappropriate processes).

Referring to FIGS. 24A and 24B, a tilting pad bearing 316 for use in thesecond bearing ring 304 is shown in accordance with yet anotherembodiment. The tilting pad bearing 316 includes a base layer 322 and asingle PCD element 326. The PCD element 326 may be configured to includea diamond table and a substrate such as has been described hereinabove.In one embodiment, the PCD element 326 may be formed of a single cuttingtool blank which is subsequently bonded to the base layer 322. It isnoted that in such an embodiment, the thickness of the diamond layer inthe PCD element 326 will need to be of sufficient thickness to accountfor the concave bearing surface that will be formed (either throughvarious fabrication processes prior to assembly, or to account for theformation of such a surface due to wear).

Referring to FIGS. 25A and 25B, a bearing ring 302 is shown inaccordance with another embodiment. The bearing ring 302 includes a body350 forming a base layer and a plurality of bearing elements 352 thatare formed as individual PCD elements. The PCD elements may each beconfigured to include a diamond table and a substrate such as has beendescribed hereinabove. However, rather than exhibiting a geometry thatis elongated with a substantially trapezoidal cross-section (with anoptional arcuate bearing) such as described with respect to theembodiment shown in FIGS. 21A and 21B, the PCD elements aresubstantially cylindrical and arranged in a plurality of rows extendingaxially along the body 350 to define a collective bearing surface. Inone embodiment, such bearing elements 352 may comprise conventional PCDcompacts which are subsequently bonded with the body 350.

Referring to FIG. 26 a bearing ring 302 is shown in accordance withanother embodiment. The bearing ring 302 includes a body 350 forming abase layer and a plurality of bearing elements 352 that are formed asindividual PCD elements. The PCD elements may each be configured toinclude a diamond table and a substrate such as has been describedhereinabove. However, rather than exhibiting a geometry that iselongated with a substantially trapezoidal cross-section (with anoptional arcuate bearing) such as described with respect to theembodiment shown in FIGS. 21A and 21B, the PCD elements may be formedfrom conventional cylindrical PCD compacts (e.g., a 19 mm or a 13 mmdiameter PCD compact) which is shaped to include two opposingsubstantially linear side surfaces. A linear (or planar) side surface ofone PCD element may abut a linear (or planar) side surface of another,adjacent PCD element. The bearing elements 352 may exhibit asubstantially trapezoidal cross-sectional geometry such that they may bearranged along the body 350 to define a collective bearing surface(e.g., such as described with respect to FIGS. 21A, 21B, 22A and 22B).

Referring to FIG. 27 another bearing ring 380 is shown in accordancewith another embodiment. The bearing ring 380 may be used, for exampleas the second bearing ring in the assembly 300 depicted in FIG. 17.However, the bearing ring 380 is not configured with tilting padbearings as is the previously described bearing ring 304 associated withthe bearing assembly 300. The bearing ring 380 includes a body 382forming a base layer and a plurality of bearing elements 384 that areformed as individual PCD elements. The PCD elements may each beconfigured to include a diamond table and a substrate such as has beendescribed hereinabove. The PCD element may be formed from conventionalcylindrical PCD compacts (e.g., a 19 mm or a 13 mm diameter PCD compact)which is shaped to include two opposing substantially linear sidesurfaces. A linear (or planar) side surface of one PCD element may abuta linear (or planar) side surface of another, adjacent PCD element. Thebearing elements 384 may exhibit a substantially trapezoidalcross-sectional geometry such that they may be arranged along n interiorradial surface of the body 382 to define a collective bearing surface.Of course, PCD elements 384 exhibiting similar geometries may be used toform tilting pad bearings if desired and used in an assembly similar tothe second bearing ring 304 described hereinabove.

Referring briefly to FIG. 28, another bearing assembly 400 is shown. Thebearing assembly 400 is configured as a radial bearing and may include afirst bearing ring 402 (shown in dashed lines) and a second bearing ring404. The first bearing ring 402 may be configured such as one of thepreviously described embodiments. The second bearing ring 404 isconfigured as a multi-lobe bearing and includes a body 406 and aplurality of bearing sets 408, each including a plurality of bearingelements 410. Each bearing element may be configured, for example,similar to the PCD elements 326 described above with respect to FIGS.18A-18C and 12. Each bearing set 408 is configured such that the radiusof curvature of its collective bearing surface is greater than theradius of the bearing surface of the first bearing ring 402. Thus, afluid film may form a wedge 412 that causes separation between the firstbearing ring 402 and the second bearing ring 404 as will be appreciatedby those of ordinary skill in the art and as illustrated in FIG. 28 (andas also illustrated in FIG. 18C with regard to other embodiments).

As mentioned above, the bearing apparatuses and assemblies disclosedabove may be incorporated into any suitable mechanical system includingany suitable rotary drill bit, motor, pump or drilling tool that mayinclude a radial bearing apparatus or thrust bearing apparatus, withoutlimitation. One example of such a mechanical system, without limitation,is shown in FIG. 29 which illustrates a pump 450. The pump 450 includesa housing 452 defining an inlet 454, and outlet 456 and a fluid flowpath 458 between the inlet 454 and the outlet 456. A pump shaft 460 isdisposed within the housing 452 and configured to rotate about an axis462 relative to the housing. Impeller structures 464 are coupled withthe pump shaft 460 and configured to convey fluid along the flow path458 from the inlet 454 to the outlet 458 upon rotation of the pump shaft460.

Various bearings may be used to maintain the position of the pump shaft460 relative to the housing 452 along the axis 462 while enabling it torotate about the axis 462. For example, a pair of radial bearings orjournal bearings 470, one near each end of the pump shaft 460, may beused to enable relative rotation of the pump shaft 460 and the housing452 while keeping the pump shaft substantially centered about the axis462. A thrust bearing 472 may also be incorporated into the pump. Forexample, a thrust bearing 472 may be disposed near one end of the pumpshaft 460 and configured to substantially limit or constraindisplacement of the pump shaft 460 along the axis 462 while stillenabling rotation of the pump shaft 460 about the axis 462 relative tothe pump housing 452.

The radial or journal bearings 470 may be configured, for example, asthe bearing assembly 300 described with respect to FIG. 17. The thrustbearing 472 may be configured, for example, as the bearing assembly 100described with respect to FIG. 1A-1C. Of course, the bearings 470 and472 may be configured according to other embodiments or include otherfeatures described herein as desired.

While certain embodiments and details have been included herein forpurposes of illustrating aspects of the instant disclosure, it will beapparent to those skilled in the art that various changes in thesystems, apparatuses, and methods disclosed herein may be made withoutdeparting from the scope of the instant disclosure, which is defined, inpart, in the appended claims. It is additionally noted that features oraspects of any embodiment described herein may be combined with otherfeatures or aspects of any other embodiment without limitation.

What is claimed is:
 1. A bearing assembly, comprising: a first tiltingpad bearing assembly including a first support body and a plurality offirst tilting pad bearings attached to the first support body andcircumferentially spaced from each other, the plurality of first tiltingpad bearings generally defining a first collective bearing surface, thefirst support body and the plurality of first tilting pad bearings beingcooperatively configured to limit tilting of each of the plurality offirst tilting pad bearings to no more than two degrees of tiltingfreedom; a second tilting pad bearing assembly including a plurality ofsecond tilting pad bearings circumferentially spaced from each other anddefining a second collective bearing surface; and a runner bearingdisposed between the first and second tilting pad bearing assemblies,the runner including a third bearing surface and a fourth bearingsurface, the third bearing surface generally opposing the firstcollective bearing surface of the first tilting pad bearing assembly,and the fourth bearing surface generally opposing the second collectivebearing surface of the second tilting pad bearing assembly; wherein: oneor more of the first collective bearing surface, the second collectivebearing surface, the third bearing surface, or the fourth bearingsurface include superhard material including a polycrystalline diamond(“PCD”) material; and the PCD material forms one or more of the thirdbearing surface or the fourth bearing surface.
 2. The bearing assemblyof claim 1 wherein the runner bearing includes a plurality of PCDelements including the PCD material that collectively form one or moreof the third bearing surface or the fourth bearing surface.
 3. Thebearing assembly of claim 2 wherein the plurality of PCD elements arespaced apart from one another such that there is a gap between adjacentones of the plurality of PCD elements.
 4. The bearing assembly of claim2 wherein one or more of the third bearing surface or the fourth bearingsurface is substantially continuous.
 5. The bearing assembly of claim 1wherein the first tilting pad bearing assembly includes a plurality ofPCD elements including the PCD material, the plurality of PCD elementsgenerally collectively forming the first collective bearing surface. 6.The bearing assembly of claim 1 wherein the first support body includesa plurality of recesses corresponding with the plurality of firsttilting pad bearings, the plurality of recesses and the plurality offirst tilting pad bearings being cooperatively configured to limittilting of each of the plurality of first tilting pad bearings insubstantially only a circumferential direction and a radial direction.7. The bearing assembly of claim 1 wherein the first support bodyincludes an annular channel and each of the plurality of first tiltingpad bearings is at least partially positioned in the annular channel. 8.The bearing assembly of claim 7 wherein the annular channel limitstilting of each of the plurality of first tilting pad bearings.
 9. Adownhole drilling tool including the bearing assembly according toclaim
 1. 10. A bearing assembly, comprising: a first tilting pad bearingassembly including a first support body including an annular channel anda plurality of first tilting pad bearings at least partially positionedin the annular channel and circumferentially spaced from each other, thefirst support body and the plurality of first tilting pad bearings beingcooperatively configured to limit tilting of each of the plurality offirst tilting pad bearings to substantially only a circumferentialdirection and a radial direction; a second tilting pad bearing assemblyincluding a plurality of second tilting pad bearings circumferentiallyspaced from each other; and a runner bearing disposed between the firstand second tilting pad bearing assemblies, the runner including a thirdbearing surface and a fourth bearing surface, the third bearing surfacegenerally opposing the plurality of first tilting pad bearings, and thefourth bearing surface generally opposing the plurality of secondtilting pad bearings.
 11. The bearing assembly of claim 10 wherein thefirst support body includes a plurality of recesses corresponding withthe plurality of first tilting pad bearings, the plurality of recessesand the plurality of first tilting pad bearings being cooperativelyconfigured to limit tilting of each of the plurality of first tiltingpad bearings in the circumferential direction and the radial direction.12. The bearing assembly of claim 10 wherein the first tilting padbearing assembly includes a leveling mechanism, and each of theplurality of first tilting pad bearings includes a protrusion engagedwith the leveling mechanism in a manner that permits tilting of theplurality of first tilting pad bearings.
 13. The bearing assembly ofclaim 10 wherein one or more of the plurality of first tilting padbearings, the plurality of second tilting pad bearings, the thirdbearing surface, or the fourth bearing surface includes superhardmaterial.
 14. The bearing assembly of claim 13 wherein the superhardmaterial includes a polycrystalline diamond (PCD) material.
 15. A pump,comprising: a pump shaft; and a bearing assembly operably coupled to thepump shaft, the bearing assembly including: a first tilting pad bearingassembly including a first support body and a plurality of first tiltingpad bearings attached to the first support body and circumferentiallyspaced from each other, the first support body and the plurality offirst tilting pad bearings being cooperatively configured to limittilting of each of the plurality of first tilting pad bearings to nomore than two degrees of tilting freedom; a second tilting pad bearingassembly including a plurality of second tilting pad bearingscircumferentially spaced from each other; a runner bearing disposedbetween the first and second tilting pad bearing assemblies, the runnerincluding a third bearing surface and a fourth bearing surface, thethird bearing surface generally opposing the plurality of first tiltingpad bearings, and the fourth bearing surface generally opposing theplurality of second tilting pad bearings; and wherein the first supportbody includes an annular channel and each of the plurality of firsttilting pad bearings is at least partially positioned within the annularchannel.
 16. The pump of claim 15 wherein the first support bodyincludes a plurality of recesses corresponding with the plurality offirst tilting pad bearings, the plurality of recesses and the pluralityof first tilting pad bearings being cooperatively configured to limittilting of each of the plurality of first tilting pad bearings insubstantially only a circumferential direction and a radial direction.